The present invention relates to an apparatus in an adjustable creasing tool which comprises two mutually co-operating creasing rollers, a male roller and a female roller, a gear wheel transmission with a housing for operation and mutual coordination of the creasing rollers, means for adjusting the mutual position of rotation of the two creasing rollers, means for adjusting the position of one of the creasing rollers along its axis of rotation, and means for adjusting the mutual spacing between the axes of rotation of the creasing rollers.
The creasing tool may be included in, for example, a machine for producing packaging material which is intended to be employed in a further machine in which the material is folded and joined together to form packages.
In existing creasing tools of the roller type, the rollers are mutually coordinated with a gear transmission with very slight flank play when in operation. On replacement of the material which is to be creased, it is necessary, in order to achieve acceptable creasing results, to adjust the mutual position between the male roller and the female roller of the creasing tool, if the material is of a different quality or has a deviating thickness. For gear transmissions intended for the above-mentioned use, a standard has as good as been developed. This implies that one of the gear wheels included in the transmission is split transversely in relation to its axis of rotation. In that the thus created parts are rotary in relation to one another, and may be mutually fixed by means of a releasable clamping element, a flank play which occurs in such instance in precision gear drives can be reduced so that the requisite accuracy may be maintained in the creasing tool.
The adjustment of creasing tools of the type under consideration here relates either to axial or mutually rotational adjustment or adjustment of the mutual spacing between the two rollers.
Axial adjustment is carried out by displacing one of the rollers and its shaft in relation to the gear transmission with the clamping element disengaged. In that the clamping element is disengaged for carrying out the axial adjustment, the adjustment of the split gear wheel will, however, also be affected so that this must be re-adjusted.
Tangential adjustment takes place with the clamping element disengaged in that the rotational position of the roller in relation to the gear wheel transmission is adjusted instead. The adjustment of the split gear wheel is also affected on this adjustment.
The adjustment of the mutual spacing between the two creasing rollers is carried out by insertion or removal of splines between the shafts of the two rollers which are pretensioned towards an engaged position. In that the split gear wheel in the gear transmission is adjustable for balancing the flank play of the transmission, the adjustment of the mutual spacing between the rollers should not involve any problems, since the adjustment is as slight as at most a few tenths of a millimetre and this may be compensated for by a new re-adjustment of the split gear wheel. However, such is nevertheless the case. It occasionally happens that adjustment of the spacing between the creasing rollers is carried out without therefore once again re-adjusting the flank play in the gear. The result will, in such instance, either be too slight a flank play, which may result in overheating the gear, or too large a flank play, which may result in a poor creasing result since the tangential adjustment fluctuates and will thereby be defective, and in that the transmission is quite simply worn out.
The problem in prior art adjustable creasing tools may therefore be summed up as follows. The adjustment of the flank play in creasing tool gears which, for achieving an acceptable creasing result, is realized by means of a transversely split gear wheel, gives rise to problems in connection with the other adjustment settings, in that this necessitates careful and accurate retro-adjustment of the split gear wheel. Since such additional retro-adjustment is both complicated and time consuming, it is perhaps not always put into effect in connection with adjustment of the spacing between the rollers, since this adjustment does not require that the releasable clamping element be disengaged. The result may be, in the event of too slight play, overheating in the gear, with consequential thermal transfer to the creasing roller of the split gear wheel, which may lead to thermal deformation, with a consequentially uneven creasing result. Too large a flank play immediately results in fluctuating, inexact creasing results and, in the long term, entails a risk of major failures, with operational downtime and heavy costs as a result.
Objects of the Invention
One object of the present invention is therefore to realize an apparatus in an adjustable creasing tool of the above-indicated type which makes for adjustment of both the position of one of the creasing rollers along its axis of rotation, as well as adjustment of the mutual spacing between the axes of rotation of the creasing tool, without the adjustment setting of the split gear wheel therefore needing to be affected.
Solution
These and other objects will be attained according to the present invention by means of an apparatus of the above-indicated type possessing the characterising features as set forth in the following.